7th pre alg -l20

lesson 20.notebook September 19, 2013

Assignment:1>Set 20 (evens) Due Tomorrow (9/20)


Lesson 20 WarmUp:

1) What is 15% of $80?

2) Using prime factorization, reduce: 625 1000

3) Simplify: 216

4) The number 9 is a member of which set(s) of numbers? [List all of them!]

5) What is a linear pair of angles?

3


Lesson 20:

*Naming Triangles...

By angles:

• 3 acute angles>acute triangle• 1 right angle>right triangle / 2 acute angles• 1 obtuse angle>obtuse triangle / 2 acute angles

By sides:

• 3 equal sides>equilateral triangle / 3 equal angles• at least 2 equal sides>isosceles triangle / 2 equal angles• no equal sides>scalene triangle / no equal angles


Formula for area of a triangle:

*base height or 1/2(base height) 2

(Base and height must be perpendicular!!)

*The SUM of the measures of the angles in a triangle

= 180 degrees


Examples Lesson 20pg. 129

A) isosceles triangle & right triangle

B) equilateral triangle & acute triangle

C) obtuse triangle & scalene triangle

D) x = y =


E)

F)

G)

H)

7th pre alg -l20

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